Graphene assisted template based LiMn₂O₄flexible cathode electrodes

Abstract

Summary In this paper, a systematic method has been developed to produce highly flexible and robust graphene/LiMn2O4 (G/LMO) and graphene/LiCr0.05Mn1.95O4 (G/LCMO) free‐standing composite cathode electrodes with increased specific capacity and improved electrochemical capability. Spinel LMO nanorods are synthesized by calcination method followed by a hydrothermal reaction technique. As‐synthesized nanorods were then embedded in a graphene layer which will in turn serve as a self‐standing binder‐free cathode electrode. Spinel LMO and LCMO nanorods with a length of 600 nm and width of 50 nm were then homogenously entrapped and distributed within the layers of conductive graphene structure. This hybrid structure will help to eliminate the use of heavy metal current collectors and electrically resistant binders or even conductive additives. A discharge capacity of 114.5 mAh g−1 is obtained after first cycle and %72 capacity retention is obtained after 250 cycles from G/LCMO freestanding samples. The enhancement in the electrochemical properties is due to the unique freestanding structure of the cathode electrodes.

Study on synthesis of spinel LiNi 0 . 5 Mn 1 . 5 O 4 cathode material and its electrochemical properties by two‐stage roasting

“…[24][25][26][27][28] By contrast with traditional LIB materials such as LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiFePO 4 , and so on. [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] LiFePO 4 is a commonly used positive electrode material for power lithium-ion batteries, which has the advantages of high safety, but its specific energy is not high, so it is difficult to meet the needs of new energy vehicles with longer driving range. The specific energy of spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) is high, the theoretical value is about 1100 Wh kg −1 , and the actual value can reach 700 Wh kg −1 .…”

“…At present, LIB is mainly used in mobile electronic equipment, and its application has begun to develop to the small size and lightweight of microelectrical appliances, as well as large electric equipment 24‐28 . By contrast with traditional LIB materials such as LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiFePO 4 , and so on 29‐45 . LiFePO 4 is a commonly used positive electrode material for power lithium‐ion batteries, which has the advantages of high safety, but its specific energy is not high, so it is difficult to meet the needs of new energy vehicles with longer driving range.…”

Preparation and electrochemical properties of Al‐F co‐doped spinel LiMn 2 O 4 single‐crystal material for lithium‐ion battery

“…[6][7][8][9] Nowadays, commercial cathode materials for lithium-ion batteries mainly include LiCoO 2 , LiNi x Co y Mn z O 2 , LiFePO 4 , and LiMn 2 O 4 . [10][11][12] Compared with other materials, spinel LiMn 2 O 4 has the advantages of high specific energy, environmental friendliness, high safety, and low price, so it is considered as one of the most promising cathode materials for lithium-ion batteries. [13][14][15][16] However, due to the mutual transformation between Mn 3+ and Mn 4+ in LiMn 2 O 4 during charging and discharging, the Jahn-Teller effect easily occurs, which leads to the collapse of the crystal structure.…”

Thermal safety studies of high energy density lithium‐ion batteries under different states of charge

“…31,32 At present, the studies about battery safety are mainly focused on only cathodes or anodes, and many studies just concentrate on coin-type half-cells as the research object. [33][34][35] In practical application, whether a battery is safe is determined by whether a full cell can be safe under both normaluse conditions and abuse conditions, with the key factor affecting safety being the battery's state of charge (SOC). 36,37 Therefore, the key research point of safety performance of new material systems should be focused on the real batteries under different SOC conditions.…”